The present invention relates to a swash-plate type rotary compressor such as a refrigerant compressor for use in an air conditioning system for vehicles.
FIG. 1 shows a conventional swash-plate type rotary compressor which comprises a housing 1, a drive shaft 2 rotatably mounted in the housing 1, and a pair of cylinder blocks 3 disposed within the housing 1. Each of the cylinder blocks 3 has formed therein a plurality of cylinder bores 3a which have their respective axes extending substantially parallel to the axis of the drive shaft 2 and which are disposed around the drive shaft 2 in circumferentially spaced relation to each other. A piston 4 is slidably fitted in each of the cylinder bores 3a for reciprocating motion therein. A swash plate 6 is mounted on the drive shaft 2 for rotation therewith in such a manner that a central bore 5a in a hub 5 of the swash plate 6 is fitted on the drive shaft 2. The swash plate 6 is engaged by the pistons 4. A thrust bearing 9 is disposed between an annular bearing surface 7 projecting from each end face of the hub 5 of the swash plate 6 and an end face of a hub 8 of each of the cylinder blocks 3. During rotation of the swash plate 6, the pistons 4 are reciprocated within the cylinder bores 3a to draw fluid and compress same.
In the conventional swash-plate type rotary compressor constructed as above, the cylinder blocks 3 are formed of aluminum alloy containing 12 weight % silicon, which has insufficient wear resistance. Accordingly, an iron liner 10 is cast on a sliding surface of each of the cylinder bores 3a, with which the corresponding piston 4 is brought into sliding contact, an aluminium alloy containing 16 weight % silicon is cast at two locations on an outer peripheral surface of the drive shaft 2 to form radial bearings 11, and bushes 12 are respectively fitted on the outer peripheral surface of the drive shaft 2 at each location between each radial bearing 11 and the corresponding thrust bearing 9, to thereby improve the wear resistance of the sliding portions of the cylinder blocks 3.
The arrangement in which a separate component part is provided on each sliding portion on the cylinder blocks 3 to improve the wear resistance has such disadvantages that the number of component items is large, the manufacturing steps are complicated, and the mass-productivity is low.